Myocardial Ischemia-Reperfusion Model

Indication and Application:

Efficacy screening of cardioprotective drugs and novel anti-IRI therapeutics, evaluation of anti-apoptotic and anti-inflammatory compounds, validation of myocardial preservation solutions or perfusion medical devices, and research on myocardial stunning and microvascular obstruction (no-reflow phenomenon).

Modeling Method:

• Open-Chest Surgical Method (Rodents): Under general anesthesia, endotracheal intubation, and positive-pressure mechanical ventilation, a left thoracotomy is performed. The left anterior descending (LAD) coronary artery is reversibly ligated using a slipknot (typically for 30 to 45 minutes). Ischemia is verified by localized myocardial blanching and characteristic ST-segment elevation on continuous ECG monitoring. Reperfusion is initiated by releasing the slipknot, confirmed by myocardial hyperemic blushing.

• Catheter-Based Balloon Occlusion (Large Animal): Under fluoroscopic guidance, an interventional balloon catheter is advanced into the LAD and inflated to induce temporary transmural ischemia, followed by deflation to establish a non-surgical, clinically relevant reperfusion model.

Clinical Relevance:

• Pathological and Treatment Alignment: Unlike permanent myocardial infarction models, this model captures the dual insult of acute ischemic deprivation followed by the paradox of reperfusion-induced injury (oxygen paradox, calcium overload, and burst of reactive oxygen species / ROS), perfectly mimicking human clinical AMI post-reperfusion therapy.

• Regulatory Translation: The acute and predictable timeline of tissue injury and subsequent fibrotic healing provides a rigorous, data-driven window to demonstrate the reduction of infarct size, making it a critical asset for regulatory data packages.

Key Evaluation Endpoints:

1. In Vivo / Surgical / Imaging:

• Continuous Electrocardiogram (ECG): Monitoring of ST-segment elevation/depression, T-wave inversion, and the detection of reperfusion arrhythmias (e.g., ventricular tachycardia or fibrillation).

• High-Resolution Echocardiography (Vevo System): Longitudinal evaluation of Left Ventricular Ejection Fraction (LVEF), Fractional Shortening (FS), and regional wall motion abnormalities at baseline, acute, and chronic recovery stages.

• Serum Biomarker Assays: Longitudinal measurement of cardiac-specific Troponin I/T (cTnI/cTnT), Creatine Kinase-MB (CK-MB), and Lactate Dehydrogenase (LDH) release following reperfusion.

2. Histopathology:

• Evans Blue and TTC Double Staining (The Regulatory Gold Standard): Performed at the end of the reperfusion period to differentiate between non-ischemic tissue (blue), the Area at Risk (AAR, red/pink), and the Infarct Area (IA, pale white), providing precise quantitative calculation of the IA/AAR and AAR/Left Ventricle ratios via automated planimetry software.

• Myocardial Infarction Morphometry: Standard H&E and Masson's Trichrome staining to evaluate neutrophil infiltration, contraction bands, cardiomyocyte necrosis, and chronic scar formation.

• Apoptosis Profiling: TUNEL assay to quantify the index of programmed cell death in the border zone of the infarcted myocardium.

3. Molecular:

• Oxidative Stress and Inflammatory Markers: Quantification of malondialdehyde (MDA), superoxide dismutase (SOD), and pro-inflammatory cytokines (IL-1beta, TNF-alpha, IL-6) via ELISA or Western Blotting.

• Cell Death Pathways: Expression profiling of apoptosis-related regulators (Bcl-2, Bax, Cleaved Caspase-3) to demonstrate the precise molecular mechanism of cardioprotective interventions.

Regulatory-Grade Data Package (OECD GLP, AAALAC, CMA, CNAS):

As an established preclinical CRO, all cardiovascular studies at HuaTeng Biotechnology are conducted under strict international quality guidelines. Our expert surgical teams utilize standardized LAD suture placement and calibrated occlusion durations to dramatically minimize variability in the Area at Risk (AAR). We deliver robust, tightly clustered data packages specifically formatted to support global IND submissions for pharmaceutical innovators worldwide.